Magnetization and demagnetization behaviours of melt-spun Pr₁₂Fe₈₂B₆ and Pr₈Fe₈₇B₅ ribbons

Nanocrystalline Pr_12Fe_82B_6 and nanocomposite Pr_8Fe_87B_5 ribbons have been prepared using a melt spinning technique. Recoil loops have been measured at 20, 200 and 300K. Demagnetization curves are analysed by dividing it into reversible and irreversible portions. High recoil loop susceptibility at low applied field and large reversible change in the demagnetization curve have been found in Pr_8Fe_87B_5 ribbons, showing that the reversible behaviours in nanocomposite permanent magnets originate primarily from the magnetically soft phase. The hysteresis in recoil loops found in Pr_8Fe_87B_5 ribbons originates from the soft phase α-Fe that suffers a stress.